I think this could be an issue when running Kdenlive on non-KDE desktops in general (I believe the effect widget does the same thing with its categories), but in the new render widget, single-clicking the name of the render profile header (containing all of the render profiles in its section) itself won't expand the list; only single-clicking the "expand" arrow to the left of it. Double-clicking the name, however, will open a "Save Profile" dialog box. When I click cancel, the dialog box closes, and the list THEN expands.

Like I said, I think the effects widget does this also (in KDE, single-clicking the name of the effect category will expand the list, in contrast to running GNOME where you need to double-click it to expand the list).

SOLUTION: if possible, would suggest it so that single-clicking the render profile names in the new widget will expand the list, and double-clicking will open up the save profile dialog box.

Reproducible: Always

Steps to Reproduce:
1. Open render widget in Kdenlive

Actual Results:  
Single-clicking only highlights the render profile header name. Double-clicking the render profile header name opens up the Save Profile dialog box, THEN expands the list after the dialog box closes.

Expected Results:  
Single-clicking expands the list, while double-clicking opens the dialog box.

Tested with Kdenlive-git 15.13.0.r6880.0a36960-1 on Antergos Linux x64 running GNOME 3.18.